chapter 15: Making Waves

The period and the frequency of a sound wave are

reciprocals of each other.

The Doppler effect refers to changes in a sound wave's

frequency caused by motion of a source or receiver

You hear a musician playing a series of notes of increasing frequency. As the frequency increases, the wave speed

stays the same

As a wave passes from one medium into another, it often happens that its speed increases with no change in frequency. Under these circumstances, the wavelength

increases

Two musical strings have the same length and tension, but string A has one fourth the mass of string B. The speed of a wave on string A is

twice the speed of a wave on string B.

The pitch of a sound is determined primarily by its

frequency

To change the fundamental frequency of a guitar string, you can

make it shorter, by pressing a finger of your left hand on the string.

Which of these lists is in order of increasing wavelength?

Third harmonic, second harmonic, first harmonic

The principle of superposition tells us that, if two waves cross paths,

the amplitude is the sum of the individual amplitudes.

A guitar is perfectly tuned. The tension on its strings is then increased. Which of the following is true?

The frequencies of sounds from the guitar are higher than before

When a wave reflects from a stationary boundary,

the frequency is unchanged.

When a wave crosses from one medium into another in which the wave speed is lower, the frequency is unchanged. The wavelength

decreases

Which of the following is a longitudinal wave?

A sound wave in a gas

Imagine you are holding a long rope under tension attached to a distant support. You can generate periodic waves by shaking the end up and down. Changing which of the following will least affect the velocity of waves along the string?

Frequency

On a day when the speed of sound in air is 340 m/s, what will be the wavelength of sound of frequency 227 Hz?

227 m

Consider possible standing wave patterns for a string fastened at each end. Discussion in the text shows that there is a

maximum possible wavelength.

A string is held taut between two supports 2.0 m apart. The longest and next-longest possible wavelengths for standing waves are

4 m and 2 m.

The speed of electromagnetic waves in air is 3.0 × 108 m/s. What is the wavelength of FM radio waves having a frequency of 3.0 × 108 Hz?

3.0 m

A fast train approaches a car waiting at a grade crossing and sounds its horn. A person in the car will notice that, compared to what it would be if the train were at rest, the horn sound's

frequency appears to be higher.

A harmonic wave has

a close correspondence to simple harmonic motion.

A vibrating guitar string has exactly one antinode in the middle of the string and two nodes at the end. You have produced an oscillation of the string at its

fundamental frequency.

When playing tennis, if you hit the ball off of the top end of the racket, an uncomfortable standing wave vibration is produced in the racket. This wave is

transverse.

Human hearing is most sensitive around 2500 Hz. If the speed of sound is 340 m/s, what is the wavelength of this sound?

0.14 m

When two strings of equal length on a guitar are played, two different pitches are heard. Comparing the waves on the lower pitch string to the higher, the waves on the higher pitch string have

a higher speed.

Sound is produced by a pipe that is closed on one end. The standing waves must have

at least one node in the pipe.

To excite the second harmonic in a jumprope, you have to change the frequency from the fundamental. The new frequency must be

the same as the fundamental frequency, but you'll need a larger wavelength.

Which general pattern holds for various excited states in standing waves on a rope or string fixed at both ends?

More antinodes means shorter wavelengths

Blowing gently across the top of a soda pop bottle gives you a musical note at a certain fundamental frequency. This is most similar to

an organ pipe.

An antinode in a standing wave is the location that appears to ________ (describe behavior) from equilibrium.

move away

The number of cycles of a periodic wave passing a point in space per second is called the ________ of the wave.

frequency

The product of the frequency of a periodic wave times its wavelength gives the ________ of the wave.

speed

The distance between successive nodes for a standing wave pattern is ________ the wavelength (give multiple or fraction).

half

Increasing the air temperature inside an organ pipe, neglecting any expansion of the pipe, will ________ the frequency of the fundamental tone.

increase

Sound waves in water have a higher ________ than sound waves in air.

speed

Constructive interference is a result of two waves arriving at a point ________.

in phase

Mechanical wave motion is a phenomenon in which there is a transport of ________ without net motion of the medium.

energy

Standing waves on a string produce a series of possible tones known as ________.

harmonics

An organ pipe open only at one end will have a displacement node at the ________ end.

closed

When fans do "the wave" at a sports stadium, it is a ________ (transverse or longitudinal) wave.

transverse

The lowest frequency that can be made by a guitar string is called the ________ (2 words).

1st harmonic